Substrate treatment method

Abstract

Method for removing a portion of the binder phase from the surface of a substrate that is composed of particles of at least a first phase joined together by the binder phase, and wherein the surface is etched by contacting it with a gas flow of an etchant gas and a second gas. The second gas is one or more gases that will not react with the substrate or the removed binder phase and will not alter the oxidation state of the substrate during etching.

We claim:  
     
       1. A method for applying a coating to at least a portion of the surface of a substrate, the substrate comprising particles of a hard material in a binder phase, the method comprising the acts of: 
       removing a portion of said binder phase from said surface of said substrate by contacting said surface with a gas flow substantially free of hydrogen gas and comprising an etchant gas and a second gas for a period of time that will remove said portion of said binder phase to thereby provide an etched surface on said substrate, said etched surface comprising voids produced by removal of said portion of said binder phase, said second gas comprising one or more gases that will not react with said substrate or said portion and that will not change the oxidation state of said substrate during removal of said portion of said binder phase; and  
       applying said coating to at least a portion of said etched surface, at least a portion of said coating being deposited within at least a portion of said voids in said etched surface.  
     
     
       2. The method recited in claim  1  wherein said second gas will not react with said substrate or said binder phase removed from said surface during said removing act to form an eta phase within said voids on said etched surface. 
     
     
       3. The method recited in claim  1  wherein said second gas is one or more selected from nitrogen gas, helium gas, argon gas, and neon gas. 
     
     
       4. The method recited in claim  1  wherein said etchant gas is one or more selected from hydrogen chloride gas, H 2 F 2  gas, F 2  gas, Cl 2  gas, Br 2  gas, and l 2  gas. 
     
     
       5. The method recited in claim  4  wherein said gas flow comprises concurrent flows of hydrogen chloride gas and nitrogen gas. 
     
     
       6. The method of claim  1  wherein in said etching step said binder phase is removed from said surface to a depth of between about 3 microns to about 15 microns. 
     
     
       7. The method of claim  6  wherein in said etching step said binder phase is removed from said surface to a depth of between about 4 microns to about 6 microns. 
     
     
       8. The method of claim  1  wherein said substrate is selected from cemented carbides and cermets. 
     
     
       9. The method of claim  8  wherein said hard constituent material comprises one or more materials selected from the group consisting of: 
       a carbide material selected from the group consisting of tungsten carbide, titanium carbide, tantalum carbide, niobium carbide, vanadium carbide, chromium carbide, molybdenum carbide, and iron carbide;  
       a carbonitride of a refractory metal;  
       a nitride of a refractory metal;  
       a carbonitride of an element selected from the group consisting of W, Ti, Ta, Nb, V, Cr, Mo, and Fe;  
       an oxide of an element selected from the group consisting of aluminum, zirconium, and magnesium;  
       a boride of an element selected from the group consisting of aluminum, zirconium, and magnesium; and  
       a material selected from the group consisting of tungsten, a molybdenum-containing material, and a tungsten-containing material.  
     
     
       10. The method of claim  1  wherein said binder phase comprises one or more materials selected from the group consisting of cobalt, nickel, iron, elements within Group VIII of the periodic table, copper, tungsten, zinc, and rhenium. 
     
     
       11. The method of claim  1  wherein said hard constituent material comprises tungsten carbide and wherein said binder phase comprises cobalt. 
     
     
       12. The method of claim  1  wherein said act of removing occurs within a chamber into which said gas flow is introduced. 
     
     
       13. The method of claim  1  wherein said coating enhances the wear resistance of said substrate. 
     
     
       14. The method of claim  13  wherein said coating is comprised of one or more materials selected from the group consisting of TiC, TiN, TiCN, diamond, Al 2 O 3 , TiAIN, HfN, HfCN, HfC, ZrN, ZrC, ZrCN, Cr 3 C 2 , CrN, and CrCN. 
     
     
       15. The method of claim  13  wherein said coating is an MT-milling coating. 
     
     
       16. The method of claim  1  wherein: 
       said substrate is selected from the group consisting of metal cutting inserts, dies, punches, stamps, threading devices, blanking devices, milling devices, turning devices, drilling devices, boring devices, mining bits, drilling bits, tricone bits, percussive bits, road planing devices, wood working bits, wood working blades, drawing devices, heading devices, back extrusion devices, rod mill roll devices, and wear parts used in corrosive environments; and  
       said coating enhances the wear resistance of said substrate.  
     
     
       17. The method of claim  16  wherein said coating is an MT-milling coating. 
     
     
       18. A method for applying a coating to a substrate, the method comprising: 
       providing a substrate comprising particles of a hard material in a binder phase;  
       contacting at least the surface of said substrate with a gas flow free of hydrogen gas, said gas flow comprising an etchant gas and a second gas, to thereby remove at least a portion of said binder phase from said surface and provide voids in said surface, said second gas consisting of one or more gases that will not react with said substrate and that will not change the oxidation state of said substrate during removal of said portion of said binder phase; and  
       applying a coating to at least a portion of said substrate so that said coating is at least partially disposed within at least a portion of said voids.  
     
     
       19. A substrate coating method comprising: 
       providing a substrate including particles of a hard material in a binder phase;  
       removing at least a portion of said binder phase from said surface of said substrate by contacting said surface with a gas flow comprising an etchant gas and at least one additional gas for a period of time sufficient to remove said portion of said binder phase and to thereby provide an etched surface on said substrate, said etched surface comprising voids produced by removal of said portion of said binder phase, said gas flow free from any gas that will react with said substrate or said portion or will change the oxidation state of said substrate during removal of said portion of said binder phase; and  
       applying a coating to at least a portion of said etched surface, at least a portion of said coating being deposited within at least a portion of said voids in said etched surface.